diff options
Diffstat (limited to 'libraries/Wire/Wire.cpp')
| -rw-r--r-- | libraries/Wire/Wire.cpp | 296 |
1 files changed, 109 insertions, 187 deletions
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp index 8416525..9173234 100644 --- a/libraries/Wire/Wire.cpp +++ b/libraries/Wire/Wire.cpp @@ -25,236 +25,158 @@ *****************************************************************************/ /** - * @brief Wire library, ported from Arduino. Provides a simplistic - * interface to i2c. + * @file Wire.cpp + * @author Trystan Jones <crenn6977@gmail.com> + * @brief Wire library, uses the WireBase to create the primary interface + * while keeping low level interactions invisible to the user. + */ + +/* + * Library updated by crenn to follow new Wire system. + * Code was derived from the original Wire for maple code by leaflabs and the + * modifications by gke and ala42. */ #include "Wire.h" +#define I2C_WRITE 0 +#define I2C_READ 1 + /* low level conventions: * - SDA/SCL idle high (expected high) * - always start with i2c_delay rather than end */ -uint32 i2c_delay = 1; -void i2c_start(Port port) { - I2C_DELAY; - digitalWrite(port.sda,LOW); - I2C_DELAY; - digitalWrite(port.scl,LOW); +void TwoWire::set_scl(bool state) { + I2C_DELAY(this->i2c_delay); + digitalWrite(this->scl_pin,state); + //Allow for clock stretching - dangerous currently + if (state == HIGH) { + while(digitalRead(this->scl_pin) == 0); + } +} + +void TwoWire::set_sda(bool state) { + I2C_DELAY(this->i2c_delay); + digitalWrite(this->sda_pin, state); } -void i2c_stop(Port port) { - I2C_DELAY; - digitalWrite(port.scl,HIGH); - I2C_DELAY; - digitalWrite(port.sda,HIGH); +void TwoWire::i2c_start() { + set_sda(LOW); + set_scl(LOW); } -boolean i2c_get_ack(Port port) { - I2C_DELAY; - digitalWrite(port.scl,LOW); - I2C_DELAY; - digitalWrite(port.sda,HIGH); - I2C_DELAY; - digitalWrite(port.scl,HIGH); - I2C_DELAY; +void TwoWire::i2c_stop() { + set_sda(LOW); + set_scl(HIGH); + set_sda(HIGH); +} - if (!digitalRead(port.sda)) { - I2C_DELAY; - digitalWrite(port.scl,LOW); - return true; - } else { - I2C_DELAY; - digitalWrite(port.scl,LOW); - return false; - } +bool TwoWire::i2c_get_ack() { + set_scl(LOW); + set_sda(HIGH); + set_scl(HIGH); + + bool ret = !digitalRead(this->sda_pin); + set_scl(LOW); + return ret; } -void i2c_send_ack(Port port) { - I2C_DELAY; - digitalWrite(port.sda,LOW); - I2C_DELAY; - digitalWrite(port.scl,HIGH); - I2C_DELAY; - digitalWrite(port.scl,LOW); +void TwoWire::i2c_send_ack() { + set_sda(LOW); + set_scl(HIGH); + set_scl(LOW); } -void i2c_send_nack(Port port) { - I2C_DELAY; - digitalWrite(port.sda,HIGH); - I2C_DELAY; - digitalWrite(port.scl,HIGH); +void TwoWire::i2c_send_nack() { + set_sda(HIGH); + set_scl(HIGH); + set_scl(LOW); } -uint8 i2c_shift_in(Port port) { +uint8 TwoWire::i2c_shift_in() { uint8 data = 0; + set_sda(HIGH); int i; - for (i=0;i<8;i++) { - I2C_DELAY; - digitalWrite(port.scl,HIGH); - I2C_DELAY; - data += digitalRead(port.sda) << (7-i); - I2C_DELAY; - digitalWrite(port.scl,LOW); + for (i = 0; i < 8; i++) { + set_scl(HIGH); + data |= digitalRead(this->sda_pin) << (7-i); + set_scl(LOW); } return data; } -void i2c_shift_out(Port port, uint8 val) { +void TwoWire::i2c_shift_out(uint8 val) { int i; - for (i=0;i<8;i++) { - I2C_DELAY; - digitalWrite(port.sda, !!(val & (1 << (7 - i)))); - I2C_DELAY; - digitalWrite(port.scl, HIGH); - I2C_DELAY; - digitalWrite(port.scl, LOW); + for (i = 0; i < 8; i++) { + set_sda(!!(val & (1 << (7 - i)) ) ); + set_scl(HIGH); + set_scl(LOW); } } -TwoWire::TwoWire() { - i2c_delay = 0; - rx_buf_idx = 0; - rx_buf_len = 0; - tx_addr = 0; - tx_buf_idx = 0; - tx_buf_overflow = false; -} - -/* - * Sets pins SDA and SCL to OUPTUT_OPEN_DRAIN, joining I2C bus as - * master. If you want them to be some other pins, use begin(uint8, - * uint8); - */ -void TwoWire::begin() { - begin(SDA, SCL); -} +uint8 TwoWire::process() { + itc_msg.xferred = 0; -/* - * Joins I2C bus as master on given SDA and SCL pins. - */ -void TwoWire::begin(uint8 sda, uint8 scl) { - port.sda = sda; - port.scl = scl; - pinMode(scl, OUTPUT_OPEN_DRAIN); - pinMode(sda, OUTPUT_OPEN_DRAIN); - digitalWrite(scl, HIGH); - digitalWrite(sda, HIGH); -} - -void TwoWire::beginTransmission(uint8 slave_address) { - tx_addr = slave_address; - tx_buf_idx = 0; - tx_buf_overflow = false; - rx_buf_idx = 0; - rx_buf_len = 0; -} - -void TwoWire::beginTransmission(int slave_address) { - beginTransmission((uint8)slave_address); -} - -uint8 TwoWire::endTransmission(void) { - if (tx_buf_overflow) return EDATA; - - i2c_start(port); - - i2c_shift_out(port, (tx_addr << 1) | I2C_WRITE); - if (!i2c_get_ack(port)) return ENACKADDR; - - // shift out the address we're transmitting to - for (uint8 i = 0; i < tx_buf_idx; i++) { - uint8 ret = writeOneByte(tx_buf[i]); - if (ret) return ret; // SUCCESS is 0 + uint8 sla_addr = (itc_msg.addr << 1); + if (itc_msg.flags == I2C_MSG_READ) { + sla_addr |= I2C_READ; } - - i2c_stop(port); - - tx_buf_idx = 0; - tx_buf_overflow = false; - return SUCCESS; -} - -uint8 TwoWire::requestFrom(uint8 address, int num_bytes) { - if (num_bytes > WIRE_BUFSIZ) num_bytes = WIRE_BUFSIZ; - - rx_buf_idx = 0; - rx_buf_len = 0; - while (rx_buf_len < num_bytes) { - if(!readOneByte(address, rx_buf + rx_buf_len)) rx_buf_len++; - else break; + i2c_start(); + // shift out the address we're transmitting to + i2c_shift_out(sla_addr); + if (!i2c_get_ack()) { + return ENACKADDR; } - return rx_buf_len; -} - -uint8 TwoWire::requestFrom(int address, int numBytes) { - return TwoWire::requestFrom((uint8)address, (uint8) numBytes); -} - -void TwoWire::send(uint8 value) { - if (tx_buf_idx == WIRE_BUFSIZ) { - tx_buf_overflow = true; - return; + // Recieving + if (itc_msg.flags == I2C_MSG_READ) { + while (itc_msg.xferred < itc_msg.length) { + itc_msg.data[itc_msg.xferred++] = i2c_shift_in(); + if (itc_msg.xferred < itc_msg.length) { + i2c_send_ack(); + } else { + i2c_send_nack(); + } + } } - - tx_buf[tx_buf_idx++] = value; -} - -void TwoWire::send(uint8* buf, int len) { - for (uint8 i = 0; i < len; i++) send(buf[i]); -} - -void TwoWire::send(int value) { - send((uint8)value); -} - -void TwoWire::send(int* buf, int len) { - send((uint8*)buf, (uint8)len); -} - -void TwoWire::send(char* buf) { - uint8 *ptr = (uint8*)buf; - while(*ptr) { - send(*ptr); - ptr++; + // Sending + else { + for (uint8 i = 0; i < itc_msg.length; i++) { + i2c_shift_out(itc_msg.data[i]); + if (!i2c_get_ack()) { + return ENACKTRNS; + } + itc_msg.xferred++; + } } + i2c_stop(); + return SUCCESS; } -uint8 TwoWire::available() { - return rx_buf_len - rx_buf_idx; -} - -uint8 TwoWire::receive() { - if (rx_buf_idx == rx_buf_len) return 0; - return rx_buf[rx_buf_idx++]; +// TODO: Add in Error Handling if pins is out of range for other Maples +// TODO: Make delays more capable +TwoWire::TwoWire(uint8 scl, uint8 sda, uint8 delay) : i2c_delay(delay) { + this->scl_pin=scl; + this->sda_pin=sda; } -// private methods - -uint8 TwoWire::writeOneByte(uint8 byte) { - i2c_shift_out(port, byte); - if (!i2c_get_ack(port)) return ENACKTRNS; - - return SUCCESS; +void TwoWire::begin(uint8 self_addr) { + tx_buf_idx = 0; + tx_buf_overflow = false; + rx_buf_idx = 0; + rx_buf_len = 0; + pinMode(this->scl_pin, OUTPUT_OPEN_DRAIN); + pinMode(this->sda_pin, OUTPUT_OPEN_DRAIN); + set_scl(HIGH); + set_sda(HIGH); } -uint8 TwoWire::readOneByte(uint8 address, uint8 *byte) { - i2c_start(port); - - i2c_shift_out(port, (address << 1) | I2C_READ); - if (!i2c_get_ack(port)) return ENACKADDR; - - *byte = i2c_shift_in(port); - - i2c_send_nack(port); - i2c_stop(port); - - return SUCCESS; // no real way of knowing, but be optimistic! +TwoWire::~TwoWire() { + this->scl_pin=0; + this->sda_pin=0; } // Declare the instance that the users of the library can use -TwoWire Wire; - +TwoWire Wire();
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